Hydraulic pump or motor



Sept. 24, 1935. R. E. FLANDERS HYDRAULIC PUMP OR MOTOR Filed Dec. .14, 1931 A. W J t /2 Patentedhsept. 24, 11935? PATENT OFFlCE 2,015,423 nrnnaumc PUMP on MOTOR Ralph E. Flanders, Springfield, Vt., assignor'to Jones & Lamson Mac hihe Company, Spring field, Vt., a corporation of Vermont Application December 14, 1931, Serial Nor-580,849

1 Claim.

This invention relates to improvements in hydraulic mechanism which can be employed as a pump or motor. It is an object of the invention to provide a pump or motor of the swash plate type having all of the advantages of that type of pump or' motor, but with improvements in structure which reduce the friction loss of the mechanism and materially lengthen its term of service. To this end, the plungers of -the motor or pump may have flat endfaces'to engage convex faces of corresponding rotatable contact elements carried by the swash plate, frictionless bearings being preferably provided to minimize wear between the engaging parts.

For a more complete understanding of the invention, reference may be had to the following description thereof and to the illustration of certain embodiments thereof on the accompanying drawing, of which Figure 1 is a fragmentarysectional view of a pump or motor embodying the invention.

Figure 2 is a perspective view of the .swash plate block shown in Figure 1. I Figure 3 is a perspective view of a pin gear to control the position of the swash plate.

Figure 4 is a fragmentaryplan view of the swash-plate ring shown imFigure .1.

Figure 5 is a perspectiveview of a spacing and locking element in the swash-plate. ring.

Figure 6 ma section onf the line 9-4 of Figure 4. y Y

Figure 7 is a fragmentary sectional view of a pump or motor including "the mechanism shown in Figure 1. 1

Figure 8 is a longitudinal, sectional view of the cage for the plungers. Figure 9 is a perspective view ring shown in Figures Land '1. The embodiment of the invention'illustrated on the drawing is hereinafter described as a pump, but it is understood that the same mech anism can readily be used-as a motor. The pump 41 includes a cage 82- haying a central bore '88. Surrounding this bore is a circular series of bores .84 open at one end to receive plungers 88 for reciprocation. therein. .The outer end face of each plunger is preferably flat. These plungers, as indicated inFlgure '7, are preferably made hollow to save weight and reduce inertia. Each plunger is slidably fitted in the outer portion of a bore 84 so as to form a variable pressure chambertherein. The inner end portion of each bore 84 communicates with the central bore 98 by two ports 88 and 81, the ports opening into the bore 88 in a transverse plane'axially spacedfrom of 'the gimbal the openings of the ports 81 into the bore 88. The cage 82 is rotatably mounted on a fixed hollow stem 90, but is held against axial movement thereon. The stem 90 has bores 9| and '92 extending longitudinally inwardly from the re- 5 spective ends of the stem but terminating at a dividing wall 93. The bore 9| opens out laterally through the wall of the stem 90 as by a port 94. The bore 92 likewise opens out through a port 95. These ports are adjacent to the di 0 v'iding wall 98 and open out in opposite directions. The cage 82 is mounted on the stem 90 in such a manner that the port '95 is in the plane of the ports86 and the port 94 is in the plane of the ports 81. It is' thus evidentthat as the cage 82rotates about the stem 90, the ports 88 are successively in communication with the port 95' and the ports 81 are successively in. communication with the port 94. Since the ports 94 and 95 are. diametrically opposed, it is evident that when any particular bore 84 is in communication with thebore 92 through the port 95., the diametrically opposite bore 94 is simultaneously in communication with the bore 9 I through the port 94.- The bores 9| and 92 in the-stem'90 serve 2 respectively as discharge and suction lines for suction line of the pump. This inward motion may be brought about by a tilted ring I89 mounted with its center in the axis of rotation of the cage 82. The ring is located in such, a manner as to engage the projecting ends of the plungers as and to rotate with the cage 82, but in its qwn plane and on an axis which is at an angle to the axis of rotation of the'cage. Hence each plunger 95 as it swings around the axis of the cage 82 bears alternately against the high and low sides of the ring I80. As each plunger travels from the high side to the low side, it is forced inwardly, thus forcing'oil through either the'port 94 or the port (according to the di-, rection of tilt of the ring) while the plunger opposite thereto is moving from the low side of the ring to the high side and is receiving oil into its bore 84 through the other port. In order to minimize frictional resistance and to reduce wear of the parts, the ring I" is preferably provided with a series of rotatable buttons m. these buttons being set into holes in the face of the ring I which is presented to the plungers 05, and preferably mounted on ball bearings I02 which permit free rotation of the buttons IN. The buttons may be held in place by suitable retaining elements I00 driven into a shallow groove with undercut edges and overlapping portions of adjacent buttons (Figures 4 and 5). Each buttonisformed with a rounded face, as shown in Figures 6 and 7, to engage the flat end face of a .plunger 05. It is evident from Figure 7 that as the pump rotates,- the point of contact between the plungers and the buttons shifts back and forth between the inner and outer edges of the buttons. This results in. relative movement between each button and the end of its respective plunger 85. The ball bearings I02 facilitate such relative movement with a minimum of resistance and wear. Moreover, since the rounded faces of the buttons IOI bear on the fiat end faces of the plungers 05, the direction of pressure is perpendicular to the end face no matter what the di-' rection of tilt of the buttons IOI may be. Hence in spite of a continual change in the angle of thrust between each plunger and its button, the actualpressure on the plunger is in the direction of its length. Except for slight frictional stresses, the plun'gers are thus free from lateral stresses which would otherwisetend to cause wear between the plungers and their bores, with resultant leakage and loss of efliciency. According to the present invention, all the lateral stresses incident to the angular thrust between the plungers and buttons are taken up by the buttons, the ball bearings I02 being provided to take care of such stresses. The swash plate block I04 of the pump, as illustrated in Figure 2, is semi-cylindrical in shape and has a semi-circular rib I05 on the cylindrical face to anchor it against axial move-- ..ment. The block I04 also has a first face I06 "against which the ring I00 bears, this ring being supported by a suitable ball bearing I01 which surrounds and is centered by a raised circular rib I00. The block I 04 is pierced by a central bore I I0 to receive the stem 00, this bore being flared in one dimension to pennit the swash plate to rock through a sufficient angle. The rate of delivery of fluid from the pump, when the speed of rotation of the pump is constant, is determined by the angle of tilt of the swash plate I04. It is .evident from Figure 7 that if the swash plate adjusted to a position in which the plane face I 06 is perpendicular to the axis of'the stem 00, there will be no high or low side to this face. Hence the rotation of the cage 02 will produce no delivery of fluid from the pump. If the swash plate istilted to its maximum angle in onedirection, as, for example, that illustrated in Figure 7, the fluid is discharged into the bore OI of the stem 00. If the angle of the swash plate is reversed, the fluid is discharged into the bore 02 so that the flow around the circuit ough the motor is reversed. It is obvious that the direction of oil discharge could also be reversed by reversing the direction ;of rotation of the cage 02. In the structure illus- 'trated, however, the cage 02 is adapted to be driven in one direction only so that reversal of the pump is obtained only by reversing the angle of the swash plate, The swash plate is preferably controlled by a Geneva type of motion resulting from the. engagement of one or the other of a ..tions between these two members.

K pair of pins III and I I 2 in respective channels I I3 and I I4 in an end face of the block I04. These pins are mounted in the end of a hub member I II which in turn is mounted on a shaft 0. When this hub member I I5 is turned counter-clockwise, as in liigure 7, the pin III enters the channel II I and swings the block I04 in a clockwise direction. When the hub member II! is turned in a clockwise direction, the block I04 is swung in the opposite direction. As the pin II I is leaving the 10 outer end of the channel Hi, the pin III enters the outer end of the channel I I4 and takes up the load, moving the block I04 until it reaches its maximum angle of tilt in the opposite direction. This Geneva type 'of motion is advantageous in that it permits of a relatively fine adjustment of the angle of the swash plate when the swash plate is in or near its neutral position, that is, a given amount of rotation of the hub member H5 produces minimum corresponding rotation of the swash plate when the latter is in its neutral position with its plane face I06 perpendicular to the axis of the stem 82.

Synchronous rotation of the pump cage 02 and the ring I00 is accomplished by gimbal connec- As shown in Figures 1 and'9, a gimbal ring I" is provided with a pair of outwardly projecting trunnions III which rest in a pair of notches III in the cage 82 so thatthe ring I" can rock on the axis of these trunnions. A second pair of trunnions III project from the ring I00 and enter a pair of holes in the ring III arranged 90 from the trunnions I I9. The inner end portions of the trunnion pins I I8 are enlarged as at I20 to hold the pins in place. -Thus the swash plate ring I00 can rock on any of its diameters by reason of its gimbal mounting. This permits the ring I00 to be driven by its connection with the cage 02 to rotate in its own plane, the angle of which, relative to the axis of the cage, is determined by the block I04 and may be adjusted by movement of the block. The cage 82 may be provided with a ring of gear teeth 40 adapted to'mesh with any suitably located gear ,(not shown) through which the pump or motor may be driven by or may drive other mechanism not shown.

It is obvious that various modifications and changes may be made in the specific embodiment of the invention herein shown and described without departing from the spirit and scope as deflned by the appended claim.

I claim:-

A fluid pump or motor comprising a rotatable cage having bores therein parallel to the axis of rotation of the cage, a plunger reciprocable in each said bore, a swash .plate rockable on an axis perpendicular to said axis of rotation, a ring rotatably mounted on said plate, said ring having contact elements forengagement with respective w plungers, means for rotating said cage and ring y in synchronism, and means for rockably adjusting said swash plate, saidadjusting means including an operating shaft and a Geneva movement connection between said shaft and said plate, said connection being so arranged that movement of said shaft results in varying rocking movement of said plate, the rate of such rocking movement being minimum when the plane of said plate is RALPH E. FLANDERS. 

